Telephone system



Feb; 16 1926.

E. 'VON NOSTITZ TELEPHONE SYSTEM `Filed, Dec. 14, 192s A TTORNEY Patented Feb. 16, 1926.

UNITED STATES PATENT OFFICE.L

ERICH VON NOSTITZ, OF BROOKLYN, NEW YORK, ASSIGNOR TO AMERICAN TELEfI-ION p AND TELEGRAPH COMPANY, A CORPORATION 0F NEW YORK.

TELEPHONE SYSTEM.

Application filed December 14, 1923. Serial No. 680,718.

To aU whom it may 0077007771:

Be it known that l, Enron voN Nos'rrrz, residing at Brooklyn, in the county et Kings and citate of New York, have invented certain linproveinents in Telephone Systems, et which the 'following is a specification.

This invention relates to telephone sys`` tems, and more particularly to call circuits for such systems over which trunk assignments may bemade. u

At night and other times, when the traffic conditions do not warrant the employment et a iiull stati of operators at all the positions at a telephone switchboard used as a tandem center, it is the practice to group several positions, so that incoming calls at these positions may be answered by one operator at a single position and completed to the terminating otlice by the saine operator. ln the case ot' grouped call circuit positions at a tandem switchboard, itI has been necessary heretofore ior the operator at a grouped `position to Walk back and fort-h i'rom one position to anotherin response to incon'iing calls at the different positions of the group in order to obtain the number of an idle trunk to assign'a calling operator and to obtain the number of an idle outgoing trunk from a called operator so as to complete the connection. It is an object of this invention to eliminate these time-consuming operations, and permit a tandem operator to answer an incoming call and communicate with the distant oliice Where the call is completed in a simple and etlicient manner. JAnother object of lthe invention consists in preventing connection of and applying a` tone signal to all incoming call circuits `during the interval of connection of the tandemv operator and called operator, as `an indication to a calling operator that the tandem operator is busy, so that confusion may be eliminated in the assignment ot the trunks tothe incoming operators. Other and further objects of the invention will appear more fully hereinafter.

Theinvention may nowbe more fully understood irom the following description, ivhen read in connection Wit-h the accompanying drawing, the iigure of4 Which shows a circuit dia-gram illustrating one embodiment of the invention. Referring to the drawingthe numerals 1, 2 and 3 each represent an incoming call circuit t'rom other offices terminating in keys 4l, 5 and 6, respectively, at different posi-` 7, 8V and 9, designate conductors connected at each position to additional keys and call circuits leading tov other distant oiiices. 14,

15 and 16 represent groupkeys which serve` when actuatedto connect their positions to` gather, so that an operatorat such connected position may answer an incoming call to any of the positions of the group. A relay is associated with eac-h position, as is indicated at17, 18 and 19, for connecting a tone over the conductors 20 to all incoming call circuits when the tandem operator `is engaged in completing a connection.

ln the normal operation of the improved circuit, it may be assumed `for Vthe purpose o1Lx illustration that an incoming call from a distant oliice is over conductors 1,.thecir cuit continuing through the upper and lower contacts ofkey 4L, normal rcontacts of relay 17, leit and right-hand inner contacts, respectively, of key 14 to the tandem operators telephone set. When this circuit is closed a talking connection is completed between the distant calling voperator and the tandem operator and the former operatorV may announce the nurnber'land name of the exchange desired whereupon the tandem operator assigns a trunk over Which the connection is to be established. The tandem operator new actuates a call circuit keyconnected to the talking `conductorsterminating at the called exchange. Assumingr the exchange desired is that connected with conductors 10, key 7 is depressed and thetandem operators set connected to said conductors through contacts 21 and 40 of said key.l conductors 23 and 24, left and right-hand inner normal contacts of key 111 to the tip andring conductors of said set. The actuation of key 7 also closes a circuitv through its contact 22 from ground, over conductor 25, through Winding of high resistance relay 26 to battery causing the operation of relay 26, which, inturn, closes a circuit through its make "contact from battery, through the winding of relay 17 to ground causing the cnergization of the latter relay. Relay 17 upon operating connects tone through its make contacts over vconductors 20, so that during the interval key 7 1s actuated, an operator on an incoming call circuit cannot obtain connectionlwith the tandem operator,

such an attempt/causing tone to` be impressed upon the call circuit as an indication that the tandem operator is busy. lVhen talking connection between the tandem operator and the operator'at the called exchange is established, a trunk is assigned to the ,tandemloperatoig who then releases key 7 and connects a tandem trunk With the trunk assigned and the connection between the calling and 'called exchanges is completed in a Well understood manner.

In the operation'of the improved circuit that just described in, connection with key 141. An incoming call on one of the other positions, :tor example, an incoming call over conductors 1', is completed through the contacts of key't, normal contacts of relay 17left-hand `inner normal contacts of key 14,- make'conta'cts 27 and' 28 of said key, conductors 29 and 30, contacts 31, 32, and 33, 34, of key7 15 to the operators set.' The operator connectedlwith vtheincoming call cirlcuitfl can now transmit to the tandem operator connected With key 15, the name and number of the oilice and line desired. The tandem y,operatorassigns a trunk to the calling operatoi` over which a connection is to be made, and to complete the call to the Wanted officev depresses a keyk at the incoming called position associated with an outgoing trunk to that loiiice. i Assuming that this is key 7, the operators telephone set is connected tothe outgoing conductors 10 through the contacts 21 and 10, conductors 23 and 24, inner left-hand normal contacts and make contacts 27 and 28 of key 14, conductors 29 and 30, respectively, normal contacts 31, 32 andBB, `341i of key 15 to the. Voperatos telephone set associatedwith key15. The closing ofthis circuit establishes a talking connection between the tandem and distant operators A so that the number of an idle trunk `may be transmittedto the tandem operator,v

Without the tandem operator being required to Aagain change her position. The tandem operator connects one 'end' of the tandem trunk, the opposite end of which is connected with the l calling oice, to the trunk assigned by the distant operator,` which extends to the distant or called o-Hice. The connection may be now completed in a Well understood manner. During the operation of key 7,k a circuit is closed through its grounded contact, over conductor 25 and Winding of relay 26 to battery, thus causing the operation of relay 26. The energization of this relay through itsmake contact closes a circuit from battery and winding of relay 17 to ground, which causes the operation of the latter relay, vand'connects a tone to the armatures thereof. The operation of key 7 alsocauses the operation Vof high yresistance relay 38 by'a circuit extending from the grounded contact of said key, make contact 41 of key 14, conductor 39,' Winding of relay 38 to battery. The operation of relay 38 in turn causes the operationl ot relay 1S over a circuit frombatte'ry, make contact of relay 38, Winding of relay 18`to ground. In a similar manner t-he high resistance relays are operatedat all positions grouped to the one at which the tandem'ioperator is located so that tone will be connected to a call circuit incoming at any position of the group and transmitted to any incoming operator desiring to communicate with the tandem operator during the interval the latter opcrater is connected to an outgoing call circuit.y Thisservespas an lindication that thev tandem operator is busy and connection cannot be had at that time.

lVhat is claimed is:

1. A plurality of outlying telephone exchanges, a tandem oiiice having trunks extending to each outlying telephone exchange, means at the tandem office to interconnect the trunks to each outlying exchange, incoming call circuits extending from outlying ex-` changes to the tandem oice, outgoing call circuits extending from they tandem ofice to othery outlying exchanges, means whereby the operators at said irst mentioned outlying exchanges may converse with the tandem operator over said'rst mentioned call circuits, means at the tandem otlice to complete a talking connection over said second mentioned call circuits to enable the tandem operator to converse with operators at the other outlying exchanges for the ypurpose of passing information with reference to the establishment ot' connections for said trunks, means associated with each position for transferring incoming call circuits to a grouped position, and means associated kwith each position'of a group yto prevent talking connection between the tandem office and all incoming call circuits and connect tone to lsaid incoming call circuits during the interval the tandem oiiice is connected With an outgoing call circuit.

2. A plurality of outlying telephone exchanges, a tandem office having trunks extending to each outlying exchange, means at the tandem oiii'ce to interconnect trunks to each outlying exchange, a plurality of operators positions at said tandem oiiice, call circuits incoming from certain of said outlying exchanges to one of said positions, call circuits incoming from other outlying exchanges to other of said positions, outgoing call `circuits extending from each of said positions to outlying exchanges, means to group the conn-ection of incoming call circuits at certain ol said positions to a single transferred position, means at said transferred position to connect with outgoing call circuits to outlying exchanges :tor the purpose of passing information with reference to the establishment of connections for said trunks, and means associated with each position of the group at the transferred position to connect tone to incoming call circuits during the interval of connection between said single transferred position and an outgoing call circuit. n

3. A telephone system comprising a plurality oi telephone exchanges, a tandem ofice having a plurality of positions, incoming call circuits from the. telephone exchanges to the tandem oflice positions, outgoing call circuits from the tandem ofiice positions to a plurality of telephone exchanges, switching means associated with each `position for transferring call 'circuits normally'incoming thereto to another position, means associated with each position for establishing connections over outgoing call circuits, and means responsive to the actuation of the last mentioned means for preventing talking connection oif incoming call circuits With a tandem position during the interval of its connection With an outgoing call circuit.

4C. A telephone system comprising a plu-` rality of telephone exchanges, a tandem ofiice having a plurality of positions, incoming call circuits from the telephone exchanges to the tandem ofiice positions, outgoing call circuits from the tandem o-itice positions to a plurality of outlying telephone exchanges, means at each position for answering an incoming call circuit, means at each position for establishing a connection with an outgoing call circuit,v switching means at each position for transferring incoming calls to a grouped position, and means associated with each position for connecting tone to incoming call circuits seeking connection With any position included in the group during the interval said grouped position is connected to an outgoing call circuit.

In testimony whereof, I have signed my name to this specification this 13th day of December 1923.

ERICH voN NOSTITZ. 

